The interaction of CD40 with its ligand CD40L plays a critical role in regulating immune responses. Binding of CD40L to CD40 triggers activation of the CD40 pathway which up-regulates costimulatory molecules such as CD80 and CD86. Blockade of the interaction between CD40 and CD40L by monoclonal antibodies has been shown to result in protection from autoimmunity and graft rejection in various preclinical models. Recently, in a mouse model of amyotrophic lateral sclerosis, an antibody directed to CD40L was shown to delay disease onset and prolong survival the onset of disease. (U.S. Pat. No. 8,435,514, hereby incorporated by reference). In early clinical studies, the humanized anti-CD40L antibody hu5c8 showed efficacy in patients with lupus and in patients with immune thrombocytopenic purpura. However, incidents of thromboembolism in the patients treated with hu5c8 halted further trials. Further in vitro and preclinical animal studies established that interaction of the Fc with the Fc receptor FcγRIIa caused platelet activation, and aggregation, that resulted in thromboembolic events. Various approaches have been taken to reduce or eliminate the interaction of the immunoglobulin Fc region with FcγRIIa, including introducing a point mutation in the Fc region to make an aglycosylated anti-IC40 L IgG1 which lacked Fc effector function. Other approaches use fragments of antibodies lacking the Fc region or antibodies that contain multiple amino acid substitutions in the Fc region. Although the anti-CD40L antibody, hu5c8, showed efficacy in human patients there is no anti-CD40L antibody on the market. Accordingly, there is a need for improved anti-CD40L antibodies for administration to humans that do not cause platelet activation or aggregation yet are stable and bind to CD40L.